Question

C program

To develop a C program to implement a process system call.

PROBLEM

You are to use the Ubuntu operating system to write a C program that creates a process to determine the identification of the current user of your computer. I mean if joe is the login of the current user of your computer your solution should return joe. Your solution must also provide the pid of both the parent and the child processes. You may use the fork(), getpid(), getppid(), as well as any of the exec() family of system calls.

HINT

The shell command whoami returns the current user of the system.

WHAT TO SUBMIT

You are to submit to Blackboard the following:

1. Your source code, as well as
2. any output produced by your solution that, clearly, states the following:

1. The current user of the system, and
2. information about both pids of the parent and the child processes. You are to use the following format to structure your output:

1. The current user is: name-of-the-user
2. Parent: My pid = pid-of-parent. I created child pid = pid-of-child
3. Child: My pid = pid-of-child. My parent’s pid = pid-of-parent

Note: In b) Parent is to indicate that the output produced was generated by the parent process. In a similar way, in c) Child indicates that the output was generated by the child process.

Answer 1

fork.c
#include<stdio.h>
#include<unistd.h>
int main(){
        pid_t id;
        id = fork();
        if(id==0)
                printf("This is child process with id: %d\n",getpid());
        else if(id==-1)
                printf("Error in creating child process\n");
        else
                printf("This is parent process with id: %d\n",getpid());
        return 0;

exec.c

#include<stdio.h>
#include<unistd.h>

int main(){
        char *arg[]={"sh","shell.sh",NULL};
        printf("This is in execDemo.c . Running exec\n");
        execv("/bin/sh",arg);
        //execvp("./exec",arg);
        printf("After running exec\n");
        return 0;
}

#include<stdio.h>

int main(){
        printf("This is exec.c \n");
        return 0;